JPS62115415A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain an inexpensive and simple image forming device by using a multi-color light source which permits alternate selection of emission wavelengths and ferroelectric liquid crystal optical switch element of a guest- host type for which plural kinds of dichromatic dyes corresponding to the emission wavelength of the light source are used. CONSTITUTION:Respective monochromatic light beams obtd. by color filters 3a-3c of the multi-color light source 1 are controlled by the liquid crystal optical switch element 4 and are irradiated to photosensitive paper 9. The liquid crystal optical switch is the liquid crystal optical switch element 4 of the quest-host type for which plural kinds of the dichromatic dyes having the max. absorption wavelength s respectively corresponding to the plural monochromatic light beams are used. The stage for irradiating the monochromatic light beams to the photosensitive paper 9 to expose said paper while moving the paper in an arrow L direction is repeated 3 times by moving the filters 3a-3c, by which the desired images are formed on the paper 9. The mullti-color images are then obtd. by the process for press fixing and transferring. A gradation is provided to the images simply by controlling the exposing time.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention controls low-color light selectively irradiated from a polychromatic light source using a liquid crystal optical switch element, and displays images corresponding to each monochromatic light on a photoreceptor. The present invention relates to an image forming apparatus to be manufactured.

[Background of the invention]

A type of image forming device, a liquid crystal printer uses a liquid crystal as a light switch to control the light irradiated onto a photoreceptor, and is smaller and cheaper than the conventionally widely used laser beam printer. is achieved. FIG. 9(a) shows a full-color photosensitive agent suitable for full-color liquid crystal printers.

The ones shown in (b) and (c) are known.

Next, the structure of this photosensitive paper and the image forming process will be explained with reference to FIGS. 9(a), (b), and (c).

As shown in FIG. 9(a), the photosensitive paper 15 is made by wrapping each of the coloring materials of cyan C, yellow Y, and magenta M in photocurable resins ILa to 11G on the paper 14° and the chemical 13. It is composed of microcapsules. Then, according to the types of coloring materials of cyan C, yellow Y, and magenta M,
The wavelength of the light used to harden the resins 11a to 1.1c surrounding the resins is also changed. That is, the resin 11a surrounding cyan C is cured by the emission wavelength λa of the monochromatic light m J Oa, and the m-color light source 1
Yellow Y is cured with the emission wavelength λb of 0b, and m color light @
Magenta M is cured at an emission wavelength λC of 10 c.

When the light from each of the eight medium color light sources 1-Oa to loc is appropriately controlled and irradiated onto the photosensitive paper 15, the microcapsules that have been irradiated with the light of the curable wavelength will be cured, and the microcapsules that have not been irradiated will be cured. do not. Therefore, as shown in FIG. 9(b), when the transfer paper 17 is superimposed on the photosensitive paper 15 in the above state and pressure is applied with the pressure rollers 16a and 16b, only the resins 11a to 11c of the microcapsules that have not hardened are removed. is torn, and the coloring materials inside, ie, cyan C, yellow Y, and magenta M, are transferred onto the transfer paper 17 as shown in FIG. 9(c). Therefore, by controlling the light from each of the monochromatic light sources 1.0a to 10c using a liquid crystal optical switch array having a large number of openings 5l to 8n as shown in FIG.
Any image can be formed. That is, the 11th
As shown in Figures (a), (b), and (c), three types of monochromatic light gIQa and 10b.

10c and liquid crystal optical switch elements 19a, 19b, and 19c that control the light from each monochromatic light source 10a to 10c,
The photosensitive paper 15 is exposed three times, and as shown in FIG. 11(d),
By applying pressure with the pressure rollers 16a and 16b and separating it from the transfer paper 17 as shown in FIG. 11(e), it becomes possible to perform any full-color printing.

Liquid crystal optical switch elements 19a and 19b used here.

19c is required to have high-speed response, and the device structure would be simplified if multiple types of monochromatic light could all be effectively controlled by one liquid crystal optical switch element. In terms of high-speed response, with nematic liquid crystals that have been widely used as conventional liquid crystal optical switches, the response speed for both rise and fall is at most about 0.5 m5ec, which is about 0.5 m5ec, even with dual-frequency drive. If ferroelectric liquid crystal is used, 0,2'
High-speed response of 5m5ec or less can be achieved.

FIG. 12(a) is a sectional view showing a VT structure of a birefringent liquid crystal optical switch element using the above-mentioned nematic liquid crystal. As illustrated, a transparent electrode 25a.

The liquid crystal layer 226 is sandwiched between two glass substrates 24n and 24b having 25b, and further glass substrates 24a and 24b.
It has a structure in which polarizing plates 23a and 23b are arranged on both sides.

However, in the above-mentioned birefringent liquid crystal optical switch element,
It is necessary to change the thickness of the liquid crystal layer 26 depending on the wavelength of the light to be controlled. Furthermore, as shown in FIG. 12(b), in the area on the glass substrate 24a where the upper transparent electrode 25a does not exist, no electric field is applied to the nematic liquid crystal 26, so in the case of a ferroelectric nematic liquid crystal, an intermediate state is formed. As a result, light leaks out. Therefore, as shown in FIG. 12(b), it is necessary to provide a light-shielding mask 28 like chrome on the lower electrode 25b in a region facing the gap between the upper electrode 25a, which complicates the structure of the liquid crystal optical switch element. Become. Therefore, in the conventional liquid crystal optical switch element, it is necessary to adjust the thickness of the liquid crystal 26 and provide a blocking mask 28, which causes the problem that the R15 construction is troublesome, time-consuming, and expensive. In addition, the first
In FIG. 2(b), 27a and 27b are alignment films.

On the other hand, in the guest-host effect type optical switch element, as disclosed in Japanese Patent Application Laid-Open No. 60-263+6, a light-shielding mask is used, which takes advantage of the fact that nematic liquid crystal takes a specific orientation state even under the electric field O. A nematic liquid crystal optical switch element that eliminates the need for a nematic liquid crystal is known. In recent years, it has become known that it is possible to fabricate a monostable liquid crystal optical switch element even in the case of a strongly vI-conductive liquid crystal by selecting an alignment film. , (1st ゜Liquid Crystal Conference Lecture (Yi Proceedings, ρ1
22-123゜ [Object of the Invention] The present invention has been made in view of the above-mentioned embodiments of the prior art, and it is possible to use a single liquid crystal optical switch element to emit monochromatic light selectively selected from polychromatic light sources. It is an object of the present invention to provide an inexpensive and simple image forming apparatus that efficiently controls and forms images corresponding to each monochromatic light on a photoreceptor.

[Summary of the invention]

The image forming apparatus of the present invention controls light from a light source using a light switch element to form an image on a photoreceptor, and in particular, the light source is a polychromatic light source that can selectively select the emission wavelength; The optical switch element is a guest-host effect type ferroelectric liquid crystal optical switch element using a plurality of types of dichroic dyes corresponding to the emission wavelength of the light source, and the photoreceptor corresponds to the emission wavelength of the light source. It is characterized by having a photosensitive wavelength.

Even when using ferroelectric liquid crystal as an optical switch element,
Light leakage from between the optical switch openings is a problem, but by using a monostable ferroelectric liquid crystal optical switch element, it is possible to maintain the desired state by blocking the transmission of light in a stable state. It can be solved because it can be done. In addition, in order to efficiently control multiple monochromatic lights with a single liquid crystal optical switch, multiple monochromatic lights each having a maximum absorption wavelength corresponding to each of the multiple monochromatic lights selectively selected from a polychromatic light source and irradiated with a plurality of monochromatic lights are required. This problem can be solved by using a guest-host effect type liquid crystal optical switch device using different types of dichroic dyes.

As shown in FIG. 2, the guest-host effect type liquid crystal optical switch element includes a ferroelectric liquid crystal layer 32 and a pair of transparent electrodes 31a.
, 31b are formed on the surface of the glass substrates 30a, 30.
It has a structure in which one polarizing plate 29 is placed on the substrate 30a on the light source side and held in parallel by the substrate 30a.

In addition, ferroelectric liquid crystal generally forms a layered structure perpendicular to the glass substrate, and as shown in FIGS. 3(a) and 3(b), the liquid crystal molecules 36 are arranged in two types according to the polarity of the applied electric field E. Take. Dichroic dye molecules 37a, 37b mixed at this time,
37c also takes the same arrangement as the liquid crystal molecules 36. liquid crystal molecule 36
When the molecular axis of , the absorption axis 34 of the dichroic dye molecules 37a, 37b, 37c, and the polarization axis 35 of the polarizing plate are in the positional relationship shown in FIG. Light of this wavelength is absorbed and cannot pass through the liquid crystal optical switch element. However, as shown in FIG. 3(b), when the absorption axis 34 and the polarization axis 35 are located, the light can pass through the liquid crystal optical switch element. Here, if the light source is a polychromatic light source that emits selectively selected monochromatic light,
If dichroic dyes with absorption wavelengths corresponding to the wavelengths of monochromatic light that can be irradiated are mixed into the liquid crystal, it is possible to efficiently control all the light from a polychromatic light source using a single liquid crystal optical switch element. can. Furthermore, if a monostable liquid crystal optical switch element is used, in which either FIG. 3(a) or FIG. 3(b) is in one orientation state even when no electric field is applied, as shown in FIG. As shown in Fig. 3(a), light is transmitted only when an electric field is applied in one direction (Fig. 3(a)) or blocked (Fig. 3(a)).
Figure (b)) becomes possible. Therefore, this jet-stabilized liquid crystal optical switch element can always block or transmit light even in areas where there are no electrodes.
The problem of light leakage from gaps between optical switch openings is solved. Here, the selection of whether to transmit or block light in the monostable state is to change the polarization axis 35 to the absorption axis 3 in the 1n stable state.
4, depending on which positional relationship is set in FIG. 3(a) or FIG. 3(b). In addition, 33 in the figure
indicates the direction perpendicular to the layer of liquid crystal molecules.

Next, in order to obtain a good printed image, the contrast ratio CR of the liquid crystal optical switch element is required to have a value of 10 or more, and the conditions for achieving this are described below.

Generally, the contrast ratio CR of a guest-host effect type liquid crystal optical switch element is given by the following equation.

1+ (R-1) 5in2(δ-O) where R=e
"...-1)' jIu, nh: Extinction coefficient d in the optical axis direction of the dichroic dye and in the direction perpendicular to the optical axis: Gap length δ of the liquid crystal element: In Fig. 3 (a) and (b) Angle θ between the polarization axis 35 of the polarizing plate and the direction 33 perpendicular to the layer of liquid crystal molecules: dichroic dye molecules 37a and 37b in FIGS. 3(a) and 3(b).

The angle between the absorption axis 34 of 37c and the direction 33 perpendicular to the layer of liquid crystal molecules (tilt angle) Therefore, the contrast ratio CR is 5.For any tilt value of 0, the maximum value can be determined by selecting an appropriate angle δ. CR
ml a x, and its maximum value CRm a x changes depending on the value of the tilt angle 0. In the commonly used azo dichroic dye, + at (a = 0.24), and the relationship between the tilt θ and the maximum value cR, when the gap length d = 10 μm is expressed as It will look like Figure 5.

From this figure, it can be seen that a contrast ratio Cn of 10 or more is obtained when the value of θ is between 35'' and 45°.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in more detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 is an explanatory diagram showing a first embodiment of an image forming apparatus of the present invention. As shown, a multicolor light source 1 includes a fluorescent lamp 2.
and color filters 3a and 3b.

3c, and color filters 3a and 3b.

650 nm (red) and 540 nm (
Monochromatic light having a maximum emission wavelength at 450 nm (green) or 450 nm (blue) is selectively selected and irradiated onto the liquid crystal optical switch element 4. This liquid crystal optical switch element 4 is of a ferroelectric type having monostability of the guest-host effect type, and its configuration is shown in FIG.

As shown in FIG. 6, this liquid crystal optical switch element 4 includes a transparent electrode 31a and a 60" obliquely deposited film (light distribution film) 38 of SiO.
a glass substrate 30a provided with a transparent electrode 31b and a PVA film (light distribution film) 38b subjected to a rubbing process, a liquid crystal JM 32 sealed between the glass substrates 30a and 30b, Glass substrate 30 on the light source 1 side
a and a polarizing plate 29 provided on top of the polarizing plate 29. The liquid crystal used to form the liquid crystal layer 32 is decyloxybenzylidene pea dash amino 2-methylbutyl cinnamate.
-p'-amjno -2-methylbuty
lcinnaIoate, abbreviated as Dobanbuku (1) OBA
MBC) ), to which were added 1 wt% of two types of anthraquinone dichroic dyes with maximum absorption wavelengths near 650 nm and 540 nm, respectively, and an azo dichroic dye with maximum absorption wavelengths near 450 nm. did. The thickness of this liquid crystal layer; 32 was 2 μm.

Each optical switch of the liquid crystal optical switch element 4 formed as described above has a voltage of 10V and a pulse width of 10m5ec.
When rectangular pulses were applied every 6 m5 ec, light control characteristics similar to those shown in Fig. 4 were obtained.

Furthermore, on the surface of the photosensitive paper 1 shown in FIG.
There are microcapsules formed by enclosing cyan C, yellow Y, and magenta M dyes using resins that cure at 450 nm (green) and 450 nm (blue), respectively.

According to the embodiment described above, each monochromatic light obtained by the color filters 3a, 3b, and 3c of the multicolor light source 1 is controlled by the liquid crystal optical switch element 4, and is irradiated onto the photosensitive paper 9. The liquid crystal optical switch 4 is controlled by a desired image signal. At this time, while moving the photosensitive paper 9 in the direction of the arrow, it is irradiated with monochromatic light for exposure, and this process is repeated three times while moving the filters 3a, 3b, and 3c.

As a result, a desired image (+1 image) is formed on the photosensitive paper 9. Next, a multicolor image can be obtained by the pressure bonding/transfer process shown in FIGS. 9(b) and 9(Q).

To provide gradation, the exposure time can be controlled.

Note that the photoreceptor used in the present invention includes the above-mentioned first photoreceptor.
In addition to the full-color photosensitive paper mentioned in the above embodiment, in addition to photoconductor photosensitive plates and photosensitive drums, silver salt photosensitive paper used in photography can also be considered.

Next, a second embodiment of the present invention will be described using FIGS. 7 and 8. In the first embodiment described above, the liquid crystal optical switch element 4 used an optical switch array in which the openings were arranged in a line, but as shown in FIG. Signal electrode SX, S2.・・・
If an optical switch element equipped with a matrix of electrodes consisting of . That is, if a planar polychromatic light source 1 and a matrix liquid crystal optical switch element 4, which can selectively emit monochromatic light as shown in FIG. The entire surface of the photosensitive paper 9 can be exposed at once.

Further, in the embodiment of the present invention, the color filter 3a,
Monochromatic light was selected according to 3b and 3c.

If the light emitter itself can selectively emit a plurality of monochromatic lights, the device can be further miniaturized.

Furthermore, if the selection of monochromatic light can be switched at high speed, even with an array light source or a liquid crystal optical switch, three exposures can be performed with one paper feed.

〔Effect of the invention〕

According to the present invention, a plurality of types of monochromatic light can be transmitted into one light with a simple structure.
Since the photoreceptor can be exposed to light under high-speed control using one liquid crystal optical switch element, it is possible to provide an inexpensive, small and simple full-color image forming apparatus.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a first embodiment of the present invention, FIG. 2 is an explanatory diagram showing the structure of a guest-host effect type liquid crystal optical switch element used in the present invention, and FIG. 3(a). (b) is an explanatory diagram showing the operating principle of a guest-host effect type ferroelectric liquid crystal optical switch element, Figure 4 is a waveform diagram to explain the monostability of a liquid crystal optical switch element, and Figure 5 is a diagram showing the guest-host effect. FIG. 6 is an explanatory diagram showing the structure of the guest-host effect type liquid crystal optical switch used in the first embodiment shown in FIG. FIG. 7 is a plan view showing a matrix-like electrode used in the second embodiment of the present invention, and FIG. 8 is an explanatory diagram showing a state in which the entire surface of the photosensitive paper is fogged at once according to the second embodiment of the present invention. Figure 9(a). (b) and (c) are explanatory diagrams showing the process of exposure, pressure bonding, and transfer of full-color photosensitive paper, FIG. 10 is an explanatory diagram of a conventional liquid crystal optical switch element, and FIG. 11 (a). (b), (c), (d), and (θ) are explanatory diagrams showing the process of exposure, pressure bonding, and transfer of full-color photosensitive paper when using a liquid crystal optical switch element, and FIG. 12 (a). (b) is an explanatory diagram showing the structure of a birefringent liquid crystal optical switch. 1... Multicolor light source, 2... Fluorescent light, 3a, 3b, 3c
...color filter, 4...liquid crystal optical switch element,
9...Photosensitive paper, 10a, 10b, 10
c - Monochromatic light source. DESCRIPTION OF SYMBOLS 11a, 1lb, 11c... Resin, 13... Drug, 14... Paper, 15... Photosensitive paper, 16a, 16b... Pressure roller, 17... Transfer paper, 23a , 23b... polarizing plate. 24a, 25b = glass substrate, 25 a, 25
b - transparent electrode, 26... nematic liquid crystal layer, 27
a. 27b...Light distribution film, 28...Light blocking plate, 29...Polarizing plate, 30a, 30b...-Glass substrate, 31a, 31
b-transparent electrode, 32... liquid crystal layer, 34... absorption axis,
35...Polarization axis, 36-...Liquid crystal molecule, 37a, 37
b, 37c... dichroic dye molecule, 38a... 60°
Oblique vapor deposition film, 38b...PVA film, C...cyan,
M...magenta, Y...yellow.

Claims (1)

[Claims] 1. A guest host using a polychromatic light source that emits light by selectively selecting a plurality of emission wavelengths, and a plurality of types of dichroic dyes corresponding to each emission wavelength of the polychromatic light source. A liquid crystal optical switch element that uses an effect-type ferroelectric liquid crystal to control the transmission/blocking of light from the polychromatic light source, and a liquid crystal optical switch element that has a photosensitive wavelength corresponding to the plurality of emission wavelengths and that transmits through the liquid crystal optical switch element. 1. An image forming apparatus comprising: a photoreceptor that forms an image by receiving the light. 2. The image forming apparatus according to claim 1, wherein the liquid crystal optical switch element has a monostable orientation that realizes a state of transmitting or blocking light. 3. The image forming apparatus according to claim 1, wherein the ferroelectric liquid crystal constituting the liquid crystal optical switch element has a tilt angle of 35 degrees or more and 55 degrees or less. 4. The image forming apparatus according to claim 1, wherein the plurality of emission wavelengths of the polychromatic light source are red, green, and blue wavelengths, or cyan, yellow, and magenta wavelengths. 5. The image forming apparatus according to claim 1, wherein the photoreceptor is a photosensitive paper having a large number of microcapsules in which a dye is wrapped in a photocurable resin.